Contents

PBS has many uses because it is isotonic and non-toxic to most cells. These uses include substance dilution and cell container rinsing. PBS with EDTA is also used to disengage attached and clumped cells. Divalent metals such as zinc, however, cannot be added as this will result in precipitation. For these types of applications, Good's buffers are recommended.

There are many different ways to prepare PBS. Some formulations do not contain potassium, while others contain calcium or magnesium.[1]

The most common composition of PBS (1X)

Salt

Concentration (mmol/L)

Concentration (g/L)

NaCl

137

8.0

KCl

2.7

0.2

Na2HPO4

10

1.44

KH2PO4

1.8

0.24

Start with 800 mL of distilled water to dissolve all salts. Adjust the pH to 7.4 with HCl. Add distilled water to a total volume of 1 liter. The resultant 1x PBS should have a final concentration of 10 mM PO43−, 137 mM NaCl, and 2.7 mM KCl.

Cold Spring Harbor Protocol

reagent

MW

mass (g) 10X

[M] 10X

mass (g) 5X

[M] 5X

mass (g) 1X

[M] 1X

Na2HPO4

141.95897

14.1960

0.1000

7.0980

0.0500

1.41960

0.0100

KH2PO4

136.08569

2.4496

0.0180

1.2248

0.0090

0.24496

0.0018

NaCl

58.44300

80.0669

1.3700

40.0335

0.6850

8.00669

0.1370

KCl

74.55150

2.0129

0.0270

1.0064

0.0135

0.20129

0.0027

pH = 7.4

The simplest way to prepare a PBS solution is to use PBS buffer tablets or pouches. They are formulated to give a ready-to-use PBS solution upon dissolution in a specified quantity of distilled water. They are available in the standard volumes: 100, 200, 500 and 1000 mL, and 10, 25, 50 and 100 L.[2]

If used in cell culturing, the solution can be dispensed into aliquots and sterilized by autoclaving (20 min, 121°C, liquid cycle). Sterilization may not be necessary depending on its use. PBS can be stored at room temperature or in the fridge. However, concentrated stock solutions may precipitate when cooled and should be kept at room temperature until precipitate has completely dissolved before use.